The present invention relates to the treatment of tobacco bales and more particularly to a method and apparatus for injecting steam into a bale of tobacco to moisten the tobacco and to loosen the bonds between the leaves of the bale prior to breaking the bale apart.
Tobacco bales are generally a plurality of tobacco leaves arranged in a rectangular parallelepiped in layered relationship with their leaf planes being generally mutually parallel and being generally parallel to two opposing surfaces of the bale. The other four surfaces of the bale are referred to as "grained" and are generally perpendicular to the leaf plane. The bales are held together by burlap wrapping, string or other suitable means. During forming, processing, storage and transportation of the bale, the tobacco leaves in the bale typically become stuck together and dried to some extent depending upon the environmental conditions the bale is subjected to, the characteristics of the tobacco leaves and pressure on the leaves exerted by the bale wrapping. When the tobacco is to be removed from the bale wrapping and used, it is necessary to remove the wrapping and separate the bale into predominantly individual leaves as gently as possible to minimize leaf breakage. This process is called "opening" of the bale. The breaking of the bonds between the stuck together leaves may be accomplished by moistening and heating the leaves by subjecting the bale to steaming in a vacuum chamber as in U.S. Pat. No. 3,898,996 or by steam injection into the bales as in U.S. Pat. No. 4,287,897. The steam injection device of the '897 patent includes a pair of vertical pipes between which the bale is passed by means of a conveyor belt. Steam supplied to the pipes is injected into the bale by means of a plurality of holes provided therefor in the pipes. This device suffers from a number of disadvantages including the deflection of steam by the bale and thus escape of the deflected steam without efficient penetration of the bale. Moreover, injection is effected over only a limited contact area.